Hand-held vacuum and pressure pumps are generally useful whenever vacuum or pressure is desired. Vacuum or pressure can be created, for example, by compressing (i.e. squeezing) and releasing a handle of such a vacuum and pressure pump. Generally, such squeezing and releasing causes a piston to move in a vacuum or pressure device of the pump thereby creating vacuum or pressure. Such hand-held vacuum and pressure pumps are especially useful for performing vacuum extractions during childbirth. They are also useful in the automotive industry for liquid sampling and vacuum system testing and repair.
U.S. Pat. Nos. 3,612,722, 4,775,302, 4,806,084, and 4,954,054, all issued to the present applicant, disclose hand-held vacuum and pressure pumps with compressible handles. The disclosures of these patents are incorporated herein by reference.
Generally, hand-held vacuum and pressure pumps of the prior art provide vacuum or pressure through repeatedly compressing the handles of such pumps in a stroke. Compressing the handle in a full stroke is necessary to provide the most efficient vacuum or pressure per stroke. The more the handles move per stroke the more they in turn move a piston in a cylinder which creates the vacuum or pressure. The more the piston moves in the cylinder per stroke the more vacuum or pressure is provided per stroke. It is most efficient in both time and work to provide the greatest vacuum or pressure per stroke and, therefore, to compress the handles in a full stroke.
Unfortunately, handles of the pumps of the prior art may be too large and awkward for a person with a small hand to perform the necessary full and efficient stroke. However, decreasing the size of pump handles to better fit a small hand may result in a shorter or lessened stroke and, therefore, provide a smaller or lessened amount of vacuum or pressure per stroke thereby decreasing efficiency. In addition, decreasing the size of such handles may also result in lessened leverage (due to shorter handles) thereby increasing the difficulty of compressing the handles and, therefore, decreasing efficiency.
It is therefore an object of the invention to provide a hand-held vacuum and pressure pump having a compressible handle designed for use by a person with a small hand.
It is a further object of the invention to provide a hand-held vacuum and pressure pump having a compressible handle designed for use by a person with a small hand yet capable of attaining a full stroke.
It is an additional object of the invention to provide a compressible hand-held vacuum and pressure pump having a handle designed for use by a person with a small hand without shortening the handle and without suffering a loss of leverage due to shortening the handle.
It is another object of the invention to provide a hand-held vacuum and pressure pump having a compressible handle designed for use by a person with a small hand and further designed to impede a user's hand from slipping along or off the end of the handle.